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    The Psychology Of Déjà Vu
    By News Staff | November 18th 2008 12:00 AM | 8 comments | Print | E-mail | Track Comments
    All of us have experienced being in a new place and feeling certain that we have been there before. This mysterious feeling, commonly known as déjà vu, occurs when we feel that a new situation is familiar, even if there is evidence that the situation could not have occurred previously. For a long time, this eerie sensation has been attributed to everything from paranormal disturbances to neurological disorders. However, in recent years, as more scientists began studying this phenomenon, a number of theories about déjà vu have emerged, suggesting that it is not merely a glitch in our brain’s memory system. A new report by Colorado State University psychologist Anne M. Cleary, published in Current Directions in Psychological Science, a journal of the Association for Psychological Science, describes recent findings about déjà vu, including the many similarities that exist between déjà vu and our understanding of human recognition memory.

    Recognition memory is the type of memory that allows us to realize that what we are currently experiencing has already been experienced before, such as when we recognize a friend on the street or hear a familiar song on the radio. The brain fluctuates between two different types of recognition memory: recollection and familiarity. Recollection-based recognition occurs when we can pinpoint an instance when a current situation has previously occurred. For example, seeing a familiar man at a store and realizing that we’ve seen him before on the bus. On the other hand, familiarity-based recognition occurs when our current situation feels familiar, but we don’t remember when it has happened before. For example, we see that familiar man in the store, but we just can’t remember where we know him from. Déjà vu is believed to be an example of familiarity-based recognition—during déjà vu, we are convinced that we recognize the situation, but we are not sure why. 

    Cleary conducted experiments testing familiarity-based recognition in which participants were given a list of celebrity names. Later on, they were shown a collection of celebrity photographs; some photographs corresponded to the names on the list, other photographs did not. The volunteers were told to identify the celebrities in the photographs and indicate how likely it was the celebrity’s names were on the list they had seen previously. The findings were surprising. Even when the volunteers were unable to identify a celebrity by photo, they had a sense of which names they had studied earlier and which they had not. That is, they couldn’t identify the source of their familiarity with the celebrity, but they knew the celebrity was familiar to them. Cleary repeated the experiment substituting famous places (such as Stonehenge and the Taj Majal) for celebrities and got similar results. These findings indicate that the participants stored a little bit of the memory, but it was hazy, so they were not able to connect it to the new experience.

    Cleary also ran experiments to figure out what features or elements of situations could trigger feelings of familiarity. She had participants study a random list of words. During a word recognition test, some of the words on the test resembled the earlier words, although only in sound (e.g. lady sounds similar to eighty), but the volunteers reported a sense of familiarity for the new words, even when they could not recall the earlier-presented, similar-sounding words that were the source of this familiarity. Previous research has also shown that people feel familiarity when shown a visual fragment containing isolated geometric shapes from an earlier experience. This suggests that familiar geometric shapes may create the sense that an entire new scene has been viewed before. 

    These results support the idea that events and episodes which we experience are stored in our memory as individual elements or fragments of that event. Déjà vu may occur when specific aspects of a current situation resemble certain aspects of previously occurring situations; if there is a lot of overlap between the elements of the new and old situations, we get a strong feeling of familiarity. “Many parallels between explanations of déjà vu and theories of human recognition memory exist”, Cleary concludes, “Theories of familiarity-based recognition and the laboratory methods used to study it may be especially useful for elucidating the processes underlying déjà vu experiences.”

    Comments

    briantaylor
    Doesn't really add anything to your fine article, but I wish to relate a strange phenomenon that I've been unable to find replicated anywhere, ever.
    When I was a young boy I had a lot of deja vu experiences. They became less and less as I aged to the point when I was a teenager and the might happen once or twice a year. Now in my thirties, they happen once every few years, perhaps.
    When they happened as a child, it was very clear to me that I had previously dreamt these event.
    For eg:
    One day, in grade two, I stepped to my locker, lifted the latch and opened the door. My friend came up to me and said something that made me realise that I new it was going to happen. It didn't occur to me that the scenario could have been repeated 100 times already, I KNEW it was from a dream.
    The childish insistance, looking back, still doesn't make sense, but I'm willing to dismiss it as confusion.
    However, the physical sensation that came over me at the time was accute and overwhelming dizzyness.
    It had happened before, but this was the first time I told my mom about it. She took to the "brain doctor" and they gave me an EEG. My mother said I was fine.
    The deja vu dizzyness continued and slowly, went away. I haven't had an episode for several years now.
    To be honest, I miss it.
    I've yet to meet someone who has had similar sensations.
    Brian Taylor
    scientificblogging.com/briantaylor
    I disagree with the article about deja vu. It is informative and the research tells us awesome things about the human mind and memory. I have a very similar story to Brian's which I'm sure Cleary would say is just more evidence to here theory, however I have had dreams that came true, very specific dreams. I have dreamed on three different occasions that a person in my life was pregante. Each time that person became preganate sometime within the next couple of months and was not pregnate at the time of my dream. I also have deja vu frequently; it seems to occur more often when there are extreme changes in my life. Like Brian when I was a child I had deja vu more often than when I was an adult. It is weird to stumble upon this artlicle because just recently I have had more frequent deja vu experiences and have become more curious about it. Furthermore, my sister in law whom I just moved in with has began having deja vu aswell. Also, these experiences have become more intense and longer lasting, so much to the point where I will tell whomever is near me what Im experiencing and what I feel is about to happen next. And often what happens next is eerily similar to my prediction.

    I have had similar experiences and still having them. they seem a bit diffrent to your's as it seems as though im taking a glimpse into the future. At first it freaked me out but now im used to it. i use it to help me with whats going to come. e.g. i was in a shop with my mate's and one of them was looking at a bottle. he went to put the bottle back and as he did it another one fell. i had a vision this was going to happen and when i realised i quickly turned round twisted my hand and caught the bottle. my friends were shocked by what i did. from then on they have got used to me knowing things ahead of schedule. but when i told my mum she took me to the doctor and he said i needed a scan. so we went to the hospital a few weeks later to have a scan then it took another few weeks to get the results. i got the results and we were shocked i found out i was using more of my brain than the average human. about 25% more we put it down to that but since then it has helped my life so much it is brilliant.

    Steve Davis
    Brian's experience is very interesting, and backs up the point I wanted to make that deja vu episodes are much more than a feeling of familiarity. The sensation is strong to the point of being overwhelming, so I think that basing the study on recognition is a mistake.
    Gerhard Adam
    Actually the problem may be two-fold.  In part it may relate to a recognizable event from the past, for another it may well be a recollection of a dream.  Since the dream state may connect information from various sources (real or imagined), it may well be that our "deja vu" experience is a pseudo-memory based on a dream with the attendant consequence of us thinking that a dream is coming true.

    I also think we need to be careful in assigning too much weight to recalled memories, since often our recollection is spotty and may well have been filled in (over time) with unrelated pieces of information or anecdotes.  As a result our "deja vu" experience may be a completely fabricated event which results in a sense of recognition despite contrary evidence indicating that it could never have occurred before. 
    Mundus vult decipi
    Deja-vu can complexly be explained if one can actually merge these topics: Parapsychology, Theoretical Science (time & parallel universes), Paranormal Activities (spirits), and Religion Concepts in general (throw in Greek mythology to make more sense out of it...). However, there just may be *different* types of deja-vus that we cannot easily differentiate.

    To sum it all, us humans are like lab rats in a cage trying to understand the world outside of a closed laboratory. It took a millions of years for humans to understand the world is round, but it should only take a fraction of that to understand Space-Time is not what is seems. However, not very many people will understand that time travel is impossible, yet one can possibly recognize present events as if they happened because they really came from the future, but not physically.

    I'll stop flexing a 180+ IQ.... after this... (lol) One may see the future with supporting deja-vu, but the future is not yet written on the present timeline, and can be different. To jump time or to have come from the past or the future, is to come from a parallel universe, no matter what, BUT the physical body of the person in question has never left the existing universe... Science, can probably never explain all that... Figuring out what shoes God is wearing is probably more possible. (it's on a certain Married with Children show.... lol)

    briantaylor
    This article is in the top five?
    Whoa! Deja-vu!
    Honestly I think there is some valid points made here but nothing that explains how I have seen things and know things are going to happen before they do. Sometimes i can replay a currently happening event in my head as if i've been there, done that or even seen it before. I am convinced that it has something to do with my sleep or dreams.....the feeling takes me out of my body almost as if i'm watching a movie through my own eyes that i've seen before